This is a continuation of research project NS 09871, entitled Neuropharmacology-Anesthesia and the Nervous System. Future progress in Anesthesiology will depend heavily upon basic research in Neuropharmacology. The studies will center about neurological responses to anesthetics emphasizing the value of the spinal cord in neuropharmacological research. The research projects proposed herein are direct extensions of the previous studies as well as considerable departures from past approaches, and are aimed at the study of spinal cord function modulated by anesthetics while physiological parameters are strictly maintained within normal range. The departure from past approaches defined below shows our new direction. The study utilizing extracellular single unit recording technique falls into two major categories: 1) effects of anesthetics on the dorsal horn spinal gray laminae and nuclear aggregates of feline spinal cord, and 2) effects of anesthetics on nucleus reticularis gigantocellularis. BIBLIOGRAPHIC REFERENCES: Kitahata, L.M., Ghazi-Saidi, K., Yamashita, M., Kosaka, Y., Bonikos, C., and Taub, A.: The depressant effect of halothane and sodium thiopental on the spontaneous and evoked activity of dorsal horn cells: lamina specificity, time course and dose dependence. J. Pharmacol. Exp. Ther. 195:515-521, 1975. Kitahata, L.M., Day, R.L., Kao, F.F., Motoyama, E.K., and Hardy, J.D.: Der Misserfolg der Akupunktur-Anasthesie. Munch. med. Wschr. 118:425-428, 1976.